Apparatus and method for dynamically allocating radio resource

ABSTRACT

A method for a terminal to communicate with a network using a plurality of frequency band cells, and the terminal for performing the method are discussed. The method according to one embodiment includes acquiring frequency bands information on which of frequency bands measurement can be performed and on which of the frequency bands measurement cannot be performed. The frequency bands information is acquired from outside of the terminal. The method according to the embodiment further includes performing measurement on the frequency bands on which measurement can be performed based on the frequency bands information; acquiring measurement result information on the plurality of frequency band cells based on the measurement; and communicating data with a network on the plurality of frequency band cells considering the measurement result information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of copending U.S. application Ser.No. 12/375,380, filed on Jul. 1, 2009, which was filed as the NationalPhase of PCT International Application No. PCT/KR2007/003634, filed Jul.27, 2007, which claims priority under 35 U.S.C. § 119(a) to PatentApplication No. 10-2006-0071585, filed in Korea on July 28, 2006, thecontents of all of which are hereby expressly incorporated by referenceinto the present application.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a communication device and method thatdynamically uses frequency resources, and more particularly, to a mobileterminal and a communication method that can dynamically allocatefrequencies.

Discussion of the Related Art

Current wireless communication services perform data transmission andreception using fixed bandwidths. Mobile communication systems maximizetheir performance through the arrangement of frequencies in cells andresources allocated to a specific band. A technology of transmitting andreceiving signals using a fixed band is implemented through an invariantfrequency range. A general method to provide a higher service quality(for example, a higher throughput or a greater number of users) whilecomplying with current system protocols is to divide cells into smallersections or to extend the existing system protocols according to thedemand and then to install a new infrastructure.

Conventional methods of using frequency resources are divided into atechnique based on fixed bandwidths and a technique based on scalable(or variable) bandwidths.

Systems that use the fixed bandwidth technique define protocols ofservices using various transmission/reception technologies suitable forspecific bands. These systems are characterized in that they provideservices based on fixed bands. So, if it is needed to change theirprotocols, it is necessary to change their entire service systems.

On the other hand, the scalable bandwidth technique, which is currentlypredominant, selectively applies various bandwidth options. For suchscalable bandwidth protocols, it is easier to change bandwidths and tocontrol the quality of service than fixed bandwidth protocols. However,in situations where actual services are provided, the scalable bandwidthsystem operates in the same manner as the fixed bandwidth system.

In summary, the scalable bandwidth system has an advantage in that nochange is made to technologies employed in the system even whenfrequency bands have been widened or narrowed through the scalablebandwidth technique. The scalable bandwidth system can also change thequality of service without increasing the complexity of hardware sincethe employed technologies are not changed even if frequency bands arechanged.

A new technique as an alternative to the above techniques is a CognitiveRadio (CR) technique. Mitola has suggested the CR technique in 1999 withan intention to efficiently use frequency bands. The CR technique isimplemented basically based on Software-Defined Radio (SDR). The CRtechnique scans (or searches) frequency bands to select a spectrum thatis not in use and sets the selected spectrum as a basic communicationband. That is, the CR technique can perform spectrum sensing. Accordingto the CR technique, the system can make a standalone determination asto whether to change the SDR architecture according to the type of aservice found through the searching, to change the service type or thequality of service.

Taking into consideration both the fact that various wireless servicesare provided currently and the basic target concept of the CR technique,we can see that future wireless terminals will have an integrated form.That is, future wireless terminals are expected to operate according tothe CR technique. The IEEE 802.22 currently employs the CR technique asa method to share TV bands to provide Wireless Regional Area Network(WRAN) services.

Some features of the CR technique are similar to those of somecommunication standards (or protocols) that use Industrial ScientificMedical (ISM) bands. Some standards that perform communication using theISM bands provide a protocol to recognize frequency bands and to preventcollision in wireless (or radio) resources using a method called“coexistence”. The coexistence method also uses a variety of wirelessresources through frequency detection and has common features with theCR technique.

In summary, if the communication methods are divided according to thefrequency management techniques, they can be divided into the fixedbandwidth communication method, the scalable bandwidth communicationmethod, and the CR communication method. Reference will now be made tothe communication methods according to the various techniques withreference to the drawings.

First, reference is made to the fixed bandwidth communication method.

FIG. 1 illustrates use of wireless resources in the fixed bandwidthcommunication method.

Systems such as current mobile communication systems (CDMA, GSM, etc),wireless LAN (IEEE 802.11, HiperLAN, etc), or wireless PAN (IEEE 802.15)provide services using fixed bandwidths determined at an initialstandardization stage. These bandwidths are some of the publicbandwidths or the bandwidths, the use of frequencies of which has beenauthorized by the government. The fixed bandwidth communication methodis characterized in that there is no increase or decrease in thefrequency bandwidth with time. Thus, services provided in the fixedbandwidth are optimized for the bandwidth. That is, the fixed bandwidthcommunication method uses a predetermined bandwidth, regardless of thecurrent amount of traffic.

Reference will now be made to the scalable bandwidth communicationmethod.

Services using scalable bandwidths can be divided into two types.Services of the first type are provided in the case where the terminaluses a variable bandwidth while the base station uses a constantbandwidth. Services of the second type are provided in the case whereboth the base station and the terminal use variable bandwidths.

An example of the first type is shown in FIG. 2. The example of FIG. 2may be a service of the IEEE 802.16 or 802.20 protocol using OFDM. Theexample of FIG. 2 may also be a service of the 3GPP Long Term Evolution(LTE) or the like. In the CDMA mode, the example of FIG. 2 may be aservice of Evolution Data Only (EV-DO) or Evolution Data and Voice(EV-DV), which is a method of grouping and allocating channels toterminals. In the example of FIG. 2, the total bandwidth used by thebase station is fixed and the base station allocates a specificbandwidth to the terminal. The terminal receives services through theallocated bandwidth. The bandwidth used by the base station isdetermined during installation of the system.

Reference will now be made to the scalable bandwidth communicationmethod that incorporates some features of the CR technique.

FIG. 3 illustrates a method of using wireless (or radio) resources inthe scalable bandwidth communication method that incorporates somefeatures of the CR technique. As shown in FIG. 3, the bandwidth throughwhich the base station provides services may vary with time. The exampleof FIG. 3 may be that of the IEEE 802.22 protocol. The IEEE 802.22protocol is a service model created by incorporating the features of theCR technique. That is, an available frequency band is detected in eachtime unit and the base station extends its services within the availablebandwidth. Accordingly, terminals of the IEEE 802.22 standard (orprotocol) must be able to accommodate all changing bandwidths. In theIEEE 802.22 standard, Wireless Regional Area Network (WRAN) services areprovided by sharing TV bands and each service unit is provided usingchannels that are not used in other services, basically according to achannel combination/split method. That is, when the base station detectsa TV channel that is not in use, the base station uses that TV channelto provide a WRAN service. If consecutive TV channels are availablewithin the range specified in the standard, the channels are grouped tobe used as a single band and it is possible to provide services usingthe entirety of the band. The terminal must recognize all such states ofthe channels of the base station and increase its receiving capabilityaccordingly.

Reference will now be made to the CR technique. The CR technique ischaracterized in that it is not limited to a specific frequencymanagement method. That is, the CR technique is characterized in thatthe configuration of a terminal changes according to frequency resourcesin order to more efficiently use the current spectrum (i.e., thefrequency resources).

FIG. 4 illustrates how a terminal according to the CR technique(hereinafter referred to as a “CR terminal”) uses wireless resourceswhen some of the wireless resources are not in use.

As shown in FIG. 4, the CR terminal freely examines and selects aspectrum. That is, the CR terminal monitors spectrums as shown in FIG. 4and thus can detect that wireless resources of bands 401 to 406 are notin use. Accordingly, first, the CR terminal can receive a general CRservice through bands shown with a name “Conventional service with CR”in the bands 401 and 402. The CR terminal can also create a new servicethrough the bands 401 and 402.

If the CR terminal detects that the wireless resources of the bands 401and 402 are not available any longer after time “t1”, the CR terminalcan receive the service or provide a new service through the wirelessresources of the band 403 after time “t1”. If the wireless resources ofthe band 403 are not available any longer after time “t2”, the CRterminal can select the wireless resources of the band 406 tocontinuously receive or provide the service after time “t2” as shown inFIG. 4.

If there are spectrum bands to be monitored and a region not in use isdetected in the bands, the CR terminal receives a communication servicethat is provided according to the CR technique through the region. Ofcourse, the service provided may be a fixed bandwidth service and mayalso be a scalable bandwidth service. The CR technique is characterizedin that, because frequency resources that are in use change with time incontrast to the conventional services, it requires both a protocol tomanage the change of the frequency resources and a process of learningthe frequency resources. An example of the current standard having thecharacteristics of the CR technique is an IEEE 802.22 WRAN system.

One feature of the CR technique is that it freely uses frequency bands,compared to other techniques. In the scalable bandwidth communicationmethod, bandwidths available in the communication system are presetalthough a bandwidth used changes with time and communication isperformed while the used bandwidth changes within the preset bandwidths.However, the CR technique freely scans frequency bands without thepreset restriction. The CR technique is also characterized in that, ifan available band is detected, a service is received or created throughthe detected band.

Communication protocols using the fixed bandwidth technique and thescalable bandwidth technique have the following problems.

The current system needs to be modified when there is a demand ofconsumers in the future. To meet the demand of consumers, it isnecessary to create a new standard and to provide a new system. In otherwords, systems using fixed bandwidths and systems using scalablebandwidths must always change their protocols at the desires ofconsumers. However, since it is difficult to fully meet the desires ofconsumers through a single service, various types of services areprovided, thereby reducing the spectrum efficiency. Particularly, theuse of spectrums locally and temporally changes at limited demands ofusers. That is, there is a problem in that the use of spectrums isinefficient when there are such limited demands of users. Thus, wirelessterminals will evolve based on the CR technique in order to meetchanging desires of users and to accommodate a variety of communicationtechniques.

However, no one has suggested a band utilization method and acommunication method for the CR technique. The current discussions focuson how reconfiguration to recognize and determine frequency environmentsis implemented in an SDR terminal which accommodates the conventionaltype of wireless systems without change. Although this CR operationscenario has an advantage in that it integrates all wireless terminals,it has a problem in that it fails to consider an evolution towardefficient use of spectrums while fully satisfying changing desires ofusers.

To solve the above problems, one embodiment of the present inventionsuggests a communication method and device which can utilize idlespectrums.

Another embodiment of the present invention suggests a frequencyutilization method and a communication device which efficiently addressthe demand of users.

The object of the present invention can be achieved by providing amobile terminal including a communication module including a cognitiveengine for searching frequency bands based on both a specific frequencypolicy and a service chosen by a user and selecting a specific frequencyband from the searched frequency bands; and a communication system blockincluding a platform block for performing configuration for the selectedfrequency band and at least one component block for performing dataprocessing based on a specific protocol according to the configurationof the platform block.

Preferably, the mobile terminal is based on a CR technique.

Preferably, the mobile terminal further includes a policy engine foracquiring the specific frequency policy.

Preferably, the platform block performs spectrum sensing and spectrumconfiguration.

Preferably, the component block corresponds to a specific communicationprotocol.

Preferably, the component block performs communication under control ofthe platform block.

A communication method according to the present invention is a methodfor transmitting and receiving service data in a transmitting party, themethod being capable of dynamically allocating frequencies and includingsearching frequency bands based on both a specific frequency policy anda service chosen by a user; determining a frequency band to be used bythe transmitting party according to the searched result and establishinga connection for a platform block that performs configuration for thedetermined frequency band; and establishing a connection for at leastone component block that transmits and receives service data through thedetermined frequency band.

The present invention can achieve the following advantages. First, thepresent invention allows efficient use of idle spectrums. A specificembodiment of the present invention also allows different providers toshare spectrums allocated to the providers.

An embodiment of the present invention defines a comprehensive MAC/PHYformat for CR terminals. This embodiment can provide a variety ofqualities of service (QoS) since service types usable in CRcommunication devices are implemented in platform MAC/PHY blocks(MACs/PHYs). According to an embodiment, it is possible to effectivelyeliminate channel congestion that users feel for burst traffic, comparedto the method of reducing the QoS provided to the users.

Each of the embodiments of the present invention suggests a standardprotocol form that can evolve on its own. That is, the present inventioncan provide CR terminals with a comprehensive framework for both currentwireless communication technologies and future communicationtechnologies.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 illustrates use of wireless resources in a fixed bandwidthcommunication method.

FIG. 2 illustrates use of wireless resources when a terminal uses avariable bandwidth while a base station uses a constant bandwidth.

FIG. 3 illustrates a method of using wireless resources in a scalablebandwidth communication method that incorporates some features of a CRtechnique.

FIG. 4 illustrates how a CR terminal scans and uses wireless resources.

FIG. 5A is a block diagram showing an example of a CR communicationdevice according to an embodiment of the present invention.

FIG. 5B is a block diagram showing another example of the CRcommunication device according to the embodiment.

FIG. 6 is an example block diagram illustrating the configuration of aCR processing module included in the CR communication device accordingto the embodiment.

FIG. 7A is a block diagram illustrating an example of a communicationsystem block included in the CR communication device according to theembodiment.

FIG. 7B is a block diagram illustrating another example of thecommunication system block included in the CR communication deviceaccording to the embodiment.

FIG. 8 illustrates an example of a cognitive learning method accordingto the embodiment.

FIG. 9 illustrates another example of the cognitive learning methodaccording to the embodiment.

FIG. 10 illustrates a frequency bandwidth that a platform MAC/PHYdetermines according to the amount of data to be processed by a CRcommunication device.

FIG. 11 illustrates the concept of channel configuration performed by aCR communication device.

FIG. 12 illustrates frequency bands used in areas with differentpopulations of users.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention suggests a basic structure of aprotocol for communication between a terminal based on the CR techniqueand a base station that supports the CR technique. Since the entirety ofa communication system is defined with one protocol, the conventionalcommunication protocols have a problem in that a change in the systemdue to a change in the policy of a company or the demand of consumersleads to defining a protocol. That is, the conventional communicationprotocols have a problem of having to install a new system according toa change in the demand or policy.

An embodiment of the present invention suggests details of the CRtechnique that does not require a change in the protocol even when achange has been made to the demand or policy. That is, the embodimentsuggests a communication technology which is not affected by a change infrequency bands (i.e., spectrums) due to a change in the demand orpolicy.

An embodiment of the present invention suggests basic structures thatnext-generation communication terminals and systems have and alsosuggests a frequency utilization method and a basic structure that thenext-generation communication protocol will need to have.

Reference will now be made to a hardware structure of a CR communicationdevice (for example, a terminal and a base station) suggested in theembodiments.

Blocks, other than a radio frequency (RF) processing block, of the CRcommunication device are digitized and operate based on software, incontrast to conventional terminals.

FIG. 5A is a block diagram showing an example of the CR communicationdevice.

The CR communication device may need a filtering module 501 that selectsa specific frequency band, which is part of the total frequency bands,since the CR communication device freely scans (or searches) frequencybands to receive or create a service from a specific frequency band. Thefiltering module 501 can be implemented using a bandpass filter that iscontrolled by a CR processing module 503 or a controller (not shown)that controls the general operation of the CR communication device. Thebandpass filter can pass a specific frequency band in a scalable (orvariable) manner An analog signal that passed through the filteringmodule 501 is converted into a digital signal through an analog todigital (A/D) conversion module 502. The output of the A/D conversionmodule 502 is input to the CR processing module 503. The CR processingmodule 503 performs data processing according to a variety of frequencycontrol techniques described below. The CR processing module 503 isimplemented by software and loads a module of a specific wirelessprotocol to perform desired CR processing as needed. That is, the CRcommunication device is based on the SDR.

However, there may be difficulties in implementing the communicationdevice of FIG. 5A. It is also possible to perform the CR techniquethrough a CR communication device as shown in FIG. 5B. For the currentlevel of technologies, it is difficult to convert a wireless signalreceived from a wireless channel into a baseband signal at once and itmay also be difficult to perform broadband processing and thereforeanother filter and baseband conversion through a mixer are needed. Asshown, the CR communication device of FIG. 5B receives an RF signalthrough an RF receiving module 511. The RF signal is converted into anintermediate frequency (IF) signal through a downmixing module 512 andis then filtered by a filtering module 513. That is, an output signal ofthe filtering module 513 is a signal obtained from a frequency band thatis to be used by the CR communication device. The output of thefiltering module 513 is input to the A/D conversion module 502 and anoutput of the A/D conversion module 502 is input to the CR processingmodule 503. The downmixing module 512 may downmix a signal into basebandand the downmixed signal may be filtered and converted into a digitalsignal and then be input to the CR processing module 503.

Reference will now be made in detail to the structure and operation ofthe CR processing module 503 with reference to FIG. 6. The CR processingmodule 503 is implemented by software and thus the diagram of FIG. 6illustrates a software structure of the CR processing module.

As shown in FIG. 6, the software structure of the CR processing moduleincludes communication system blocks 601, a cognitive engine 602, and apolicy engine 603.

As a software module that processes a communication signal in the CRcommunication device, each communication system block 601 performs dataprocessing for actual communication. That is, the communication systemblock 601 performs data processing of a digital signal produced byconversion of the A/D conversion module 502 using a conventionalcommunication protocol suggested in the past or a new communicationprotocol to be suggested in future. The communication system block 601includes a platform MAC/PHY (i.e., a platform MAC/PHY block) and acomponent MAC/PHY (i.e., a component MAC/PHY block) that will bedescribed later. A component MAC/PHY included in the platform MAC/PHYcan be selected by the cognitive engine 602. Specifically, if it isdecided to perform communication through a specific band selected by thefrequency band scanning (or searching) of the cognitive engine 602, thenone of the specific communication system blocks may be loaded to performcommunication. Since the communication system block 601 performs dataprocessing for actual communication, it is preferable that thecommunication system block 601 perform different data processingaccording to each layer such as PHY and MAC.

The shown communication system block 601 includes an application layer,a transport layer, a network layer, a MAC/LINK layer, and a PHY layer.The application layer is the top layer that is located nearest to theuser and provides general services associated with applications of datacommunication. The main functions of the application layer include filetransfer, email, remote login, network management, spreadsheet, wordprocessing, and the like. The transport layer is responsible forend-to-end communication between two users that communicate with eachother. Specifically, the transport layer provides a function to allowseamless and reliable data transmission without error from atransmitting end to a receiving end. That is, the transport layerprovides establishment of a connection between users, maintenance oftransmission, release of connection, flow control, error control, order(sequence) control, etc. The network layer provides connectivity androute selection between two systems that are located in differentplaces. The network layer routes packets from a source to a destination.A routing protocol selects the optimal route through a network connectedbetween the source and destination and a protocol of the network layertransfers information through the selected route.

Main functions of the network layer include data transfer, relay, routeselection, and address determination for establishing a communicationline.

The functions of the application, transport, and network layers may beimplemented within a single layer. That is, a single upper layerincluding the application, transport, and network layers may beprovided.

The MAC layer is used for reliable data transmission through a physicallink. When specific communication devices communicate with each otherthrough a specific service, the link layer is used to maintaininformation of connection between the communication devices. The PHYlayer performs a function to establish a connection through a physicalmedium between communication devices. The MAC and link layers areimplemented by a platform MAC that will be described later and the PHYlayer is implemented by a platform PHY that will be described later.

The policy engine 603 of FIG. 6 performs management frequency policy.The frequency policy is information that includes information aboutwhich bands can be scanned and which bands cannot be scanned,information about which service is provided over a specific band,information about signal power with which it is possible to performcommunication in a specific band, and the like. The frequency policyindicates a variety of control information of frequency bands which thecognitive engine 602 can scan. Since the basic concept of the CRtechnique is to freely scan (or search) frequency bands and to receiveand create a service through a frequency band found by the scanning, itrequires information about frequency policy of a country or region wherecommunication devices are located. The policy engine 603 obtains, from apolicy domain 604, information such as information as to whether or nota specific frequency band can be monitored, information as to whether ornot a specific frequency band can be used, and information about aservice that can be provided or created through each frequency band. Thepolicy engine 603 can control the operations of the communication systemblocks 601, the cognitive engine 602, and the like based on theinformation obtained from the policy domain 604. For example, when it isdecided to increase transmission power for performing data communicationthrough a specific frequency band obtained by the cognitive engine 602,it may conflict with the frequency policy of the region or country andthus it is preferable that communication be performed with transmissionpower determined under control of the policy engine 603.

The cognitive engine 602 traces instantaneous frequency band changes andperforms an appropriate countermeasure. That is, the cognitive engine602 determines which service is to be performed through which bandaccording to information provided by the policy engine 603 and the usagestate of the current spectrum (i.e., frequency band) and performscommunication protocol control and optimization of the communicationsystem block 601.

The cognitive engine 602 can receive, from a user domain 605, a specificrequest of the user of the CR communication device and can scan anexternal environment & RF channel 606 using a digital signal obtainedfrom a wireless channel. Control of the policy engine 603 or the likemay be applied even when it is decided to receive a specific servicethrough this scanning. The cognitive engine 602 can select a specificcommunication system block 601 and apply a specific configuration to itand can also perform data processing of the external environment & RFchannel 606. The operation of the communication system block 601 mayalso be controlled by the policy engine 603 according to the frequencypolicy.

If the communication system block 601 has a protocol capable ofaccommodating changing frequency bands, the cognitive engine 602 canperform communication according to the changing frequency bandenvironments through the specific configuration of the communicationsystem block 601. If the communication system block 601 cannotaccommodate changing frequency bands, the cognitive engine 602 cannotcontrol the configuration of the communication system blocks 601 so thatit only functions to select a specific communication system block 601.That is, the CR communication device selects and uses one of theconventional protocols and thus it will perform operations supportingmultimode services.

Reference will now be made in detail to the structure of thecommunication system block 601. As described above, a plurality ofcommunication system blocks 601 is provided and the cognitive engine 602can select one of the communication system blocks 601. In this case,this embodiment suggests that the communication system block is dividedinto one platform block and a plurality of component blocks included inthe platform block.

FIG. 7A illustrates an example of the communication system blockaccording to this embodiment. As shown, MAC and PHY blocks of thecommunication system block 601 include platform MAC and PHY blocks,respectively. The platform MAC includes a plurality of component MACs(i.e., component MAC blocks) (component MAC 1, 2, 3). The platform PHYincludes a plurality of component PHYs (i.e., component PHY blocks)(component PHY 1, 2, 3).

For allowing the communication system module to support changingfrequency bands, it is undesirable that the communication system moduleinclude a single protocol that specifies the entirety as in theconventional technology. It is desirable that a protocol that actuallysupports a specific service be defined through individual component MACsor PHYs and that a platform MAC or PHY which manages each component beseparately defined. That is, respective protocols of the platform MACand PHY that supports MAC and PHY are defined and protocols in the formof components that can be accommodated in each platform protocol arecreated.

The platform MAC/PHY provides a basic protocol and interface toimplement a communication system. That is, if the cognitive engine 602finds a specific frequency and selects a service, this information istransferred to the platform MAC/PHY.

The platform MAC/PHY determines which communication protocol is used toperform communication in a band determined by the cognitive engine 602.That is, the platform MAC/PHY selects one of the plurality of componentMACs/PHYs. In this case, the component MAC/PHY can provide a protocoland interface limited to a specific band. In this case, the platformMAC/PHY can set a configuration to allow communication in the banddetermined by the cognitive engine 602. That is, the platform MAC/PHY isan entity which supports a communication structure to performcommunication according to the CR technique and the component MAC/PHY isan entity which performs data processing or the like for actualcommunication.

FIG. 7B illustrates another example of the communication system blockaccording to this embodiment. The communication system block accordingthis embodiment may include one upper layer and a corresponding platformMAC/PHY as shown in FIG. 7A and may also include a plurality of upperlayers (first, second, and third upper layers) and a platform MAC/PHY asshown in FIG. 7B. A mobile terminal according to this embodiment canprovide a variety of services and thus can include a plurality of upperlayers according to the provided services.

Reference will now be made to detailed operations of the CR terminalwith reference to FIGS. 6, 7A and 7B. For example, a user of the CRterminal can choose to receive both a 3GPP mobile communication serviceand a wireless LAN (WLAN) service. This choice of the user is providedto the cognitive engine 602 through the user domain 605. The cognitiveengine 602 scans frequency bands based on frequency policy of thecountry or region under control of the policy engine 603 and discovers a3GPP mobile communication service and a WLAN service in the region wherethe CR terminal is located. In this case, the cognitive engine 602transfers this information to the platform MAC/PHY. The platform MAC/PHYloads a component MAC/PHY which processes a protocol and interface forconventional 3GPP mobile communication services and a component MAC/PHYwhich processes a protocol and wireless interface for conventional WLANservices. The platform MAC/PHY performs frequency configuration so as toprovide the 3GPP and WLAN services through the frequency band discoveredby the cognitive engine 602. Through this series of operations, the usercan receive both the 3GPP mobile communication service and the wirelessLAN service.

This embodiment suggests the protocol model as shown in FIG. 7 for theCR communication device that processes digital signals. The features ofthe platform MAC/PHY and the component MACs/PHYs can be understood fromthe above description.

The characteristics of the platform MAC/PHY can be divided into those ofsymbolic and detailed protocols according to the functions included inthe components MACs/PHYs.

The platform MAC/PHY operates as a symbolic protocol if each componentMAC/PHY independently performs spectrum sensing which is an operationfor scanning frequency bands and selecting a specific band and definesan interface according to the sensed spectrum. That is, the platformMAC/PHY performs basic control such as control to transmit data receivedfrom the cognitive engine 602 to each component MAC/PHY if eachcomponent MAC/PHY supports the CR technique.

The platform MAC/PHY operates as a detailed protocol if each componentMAC/PHY does not support the CR technique, i.e., if each componentMAC/PHY has no function to communicate with CR communication devices torecognize and estimate changing frequency environments (i.e., the usagestates of frequency bands that change with time). The componentMACs/PHYs provide interfaces to receive or provide actual services ifthe platform MAC/PHY operates a detailed protocol.

The platform MAC/PHY operates as an operating platform for the componentMACs/PHYs that provide actual services. That is, as a detailed protocol,the platform MAC/PHY communicates with CR communication devices andperforms spectrum sensing which is an operation for recognizing andestimating frequency band environments and then performs configurationof the sensed spectrum. For example, the platform MAC/PHY can set aspecific control channel in a specific frequency band and can setspecific data channels indicated by the control channel. The componentMACs/PHYs can receive services using the spectrum (for example, thespecific data channels) set by the platform MAC/PHY.

On the other hand, the component MACs/PHYs provide interfacescorresponding to specific services desired by the user, for example,interfaces corresponding to wireless services such as WLAN, mobilecommunication, WPAN, GPS, TV, and radio. The component MACs/PHYs canperform data processing of digital data received by the CR communicationdevice according to specific communication standards (for example, WLAN,3GPP, WPAN, GPS, and TV) and thus can provide interfaces correspondingto specific wireless services. The variety of interfaces of thecomponent MACs/PHYs (for example, interfaces corresponding to WLAN,3GPP, WPAN, GPS, and TV) can be freely selected under control of theplatform MAC/PHY.

As described above, the platform MAC/PHY can perform spectrum sensingand configuration for the component MACs/PHYs. That is, the platformMAC/PHY can perform spectrum sensing which is an operation for scanningand analyzing frequency bands and spectrum configuration which is anoperation for performing frequency configuration according to thesensing result. The component MACs/PHYs serve to provide and createactual services.

Reference will now be made to a detailed method for performing spectrumsensing and spectrum configuration of the platform MAC/PHY. The platformMAC/PHY performs the following four operations. First, the platformMAC/PHY performs cognitive learning in conjunction with the cognitiveengine 602. Second, the platform MAC/PHY performs dynamic servicespectrum control. Third, the platform MAC/PHY performs channelconfiguration. Fourth, the platform MAC/PHY performs payload managementfor component MACs/PHYs.

First, reference is made to the cognitive learning of the platformMAC/PHY.

The cognitive learning, which is an important part of the communicationof the CR technique, is a process for distinguishing between frequencyregions that are being used and frequency regions that are not beingused in the frequency band and determining which protocol is being usedin which spectrum. To perform the cognitive learning, it is desirablethat the CR communication device monitor and estimate frequency bandsand provide corresponding information to other CR communication devices.For example, if a CR terminal independently monitors frequency bandswhen there is a problem in communication between the CR terminal and aCR base station, there will be limitations in frequency bands that canbe monitored (for example, a limitation due to processing capacity orsignal attenuation with the distance). Even when the CR base stationindependently monitors frequency bands, the CR base station will not beable to monitor all frequency bands. Accordingly, the CR terminal and CRbase station can share their frequency band monitoring results. That is,the cognitive learning can be divided into local learning that is basedon standalone determination (or estimation) of each CR terminal anddistributed learning that is based on information provided by a numberof CR terminals on the entire network.

FIG. 8 illustrates a method for cognitive learning on a networkincluding CR terminal and a CR base station. As shown, a platformMAC/PHY of each of the CR terminals and the CR base station establishesa connection to communicate a service with each other (S801). That is,to approach the base station, the CR terminal monitors spectrums on itsown and recognizes a signal transmitted by a platform MAC/PHY of thebase station. Then, the CR terminal accesses the base station to obtainother service parameters. The step S801 may also be performed after stepS802 or S803.

S802 denotes the step of local learning Each of the CR terminals and theCR base station monitors scannable frequency bands (spectrums) anddetermines which service is being provided in which frequency band.

S803 denotes the step of distributed learning Here, each of the CRterminals and the CR base station can exchange information about whichfrequency band is empty or information about which frequency band can beused to receive a service through the local learning step. Through stepS803, each terminal transfers its independently monitored spectruminformation to the base station so that the base station can collectoverall spectrum information.

When a connection has been established between platform MACs/PHYsthrough steps S801 to S803, the platform MACs/PHYs determine and loadcomponent MACs/PHYs according to the service provided and establish aconnection between the component MACs/PHYs (S804). Then, the CR terminalaccesses a component MAC/PHY of a specific service to receive theservice and continues communication with the platform MAC/PHY whilereceiving the service.

The CR terminal performs operations for the cognitive learning in thefollowing order. First, the platform MAC/PHY obtains informationreceived from a wireless channel and transfers information of thereceived signal to the cognitive engine 602. Under control of the policyengine 603 or the like, the cognitive engine 602 transfers frequencyband scan results and information about which service is available tothe platform MAC/PHY. The platform MAC/PHY completes the cognitivelearning and gives feedback information to the cognitive engine 602 andloads a component MAC/PHY to receive an actual service. That is, thecognitive engine 602 and the platform MAC/PHY function together toperform the cognitive learning and, based on the cognitive learningresults, it is possible to determine component MACs/PHYs that areactually to be provided and also to set parameters of the determinedcomponent MACs/PHYs.

FIG. 9 illustrates a method for cognitive learning on a networkincluding CR terminal and a conventional base station.

In the case of FIG. 9, the CR terminal does not need to perform locallearning and distributed learning since the base station does notsupport the CR technique. The platform MAC/PHY loads component MACs/PHYswhich can communicate with the base station and performs configurationof each component MAC/PHY and then receives a service (S804).

Reference will now be made to dynamic service spectrum control of theplatform MAC/PHY.

The platform MAC/PHY determines a spectrum through cognitive learningand then sets how CR communication devices will set spectrums. That is,the platform MAC/PHY dynamically determines a required frequencybandwidth based on frequency band analysis results, the number ofcomponent MACs/PHYs associated with services that are provided, and thetotal amount of traffic.

FIG. 10 illustrates a frequency bandwidth that the platform MAC/PHYdetermines according to the amount of data to be processed by the CRcommunication device.

In the case of the conventional communication technology, there is alimitation to the frequency band and therefore the quality of service(for example, QoS) is reduced if the demand for the service is stillincreased after all frequency resources are used.

However, the platform MAC/PHY is based on the CR technique which freelyscans frequency bands to discover a desired service and to use afrequency band that is not in use. Accordingly, the platform MAC/PHY canfreely control the frequency bandwidth according to an increase in thetraffic. That is, bandwidths of CR communication devices form aninstantaneous borrow/lend relation. When it is necessary to traffic agreater amount of traffic, the platform MAC/PHY can perform dynamicallocation to allow use of more frequency resources. The platformMAC/PHY can also reduce the bandwidth used if the amount of traffic isreduced. The platform MAC/PHY controls the frequency bandwidth accordingto the total amount of traffic and the spectrum state. Accordingly, theplatform MAC/PHY can increase the frequency band to the maximumbandwidth capable of processing all traffic if there are sufficientfrequency bands that are available without conflicting with thefrequency policy of the country or region. The platform MAC/PHY canreset the frequency band used according to the type of a requiredservice, the channel state, and the total amount of traffic.

On the other hand, if a number of CR terminals communicate with one CRbase station, it may cause a problem of collision of frequency bandsused by the wireless terminals. Accordingly, it is preferable that eachCR communication device provide a protocol for sharing specificfrequency bands to achieve coexistence for use of the frequency bandswithout collision with other CR communication devices.

As shown in FIG. 10, if traffic is increased, the CR communicationdevice can monitor frequency bands through the cognitive learningdescribed above and can determine a service and a band to be used. Inthis case, the platform MAC/PHY can set each component MAC/PHY so as toperform communication through a wider frequency band based on the resultof monitoring of frequency bands through the cognitive learning, thenumber of component MACs/PHYs used in the service, and the increasedamount of traffic. The CR technique has an advantage in that itprocesses traffic through a wide frequency band since there is nolimitation to the frequency band in terms of the characteristics of theCR technique, provided that it does not conflict with the frequencypolicy of the region or country.

Reference will now be made to channel configuration of the platformMAC/PHY.

It is preferable that a platform MAC/PHY of each CR communication deviceperform channel configuration of a control channel and a basic datachannel for communication with other CR communication devices. In thefollowing description, this channel configuration is exemplified by acontrol channel and a basic data channel configured by a platformMAC/PHY of a CR base station.

The control channel defines bandwidths to be used by the CRcommunication device and the types of services for the bandwidths. Thecontrol channel is used for connection between platform MACs/PHYs of aplurality of CR terminals and a platform MAC/PHY of a base station. Theterm “basic data channel” refers to a channel that serves as both abasic data channel and a control channel.

FIG. 11 illustrates the concept of channel configuration performed bythe CR communication device.

A control channel 904 in FIG. 11 provides information regarding theamount of frequency resources to be used by the platform MAC/PHY, i.e.,the amount of spectrums. The control channel 904 in FIG. 11 alsoprovides channel information of a plurality of data channels 901, 902,903, 905, and 906. That is, the platform MAC/PHY of the CR terminal thatcommunicates with the CR base station establishes a connection with theplatform MAC/PHY of the CR base station through the control channel 904.Through this connection, the CR terminal can determine frequency bandsover which it can perform communication and determine which services areprovided through the frequency bands. The control channel 904 alsocontains information about the way in which the CR terminal has toaccess each channel. It is preferable that the control channel 904 bedetermined according to the results of frequency band scanning by the CRcommunication device.

The basic data channel 903 of FIG. 11 may include information that canbe included in the control channel 904. That is, the basic data channel903 may be a channel extended from the control channel. For example,when the CR base station must provide a service through a broad band, aproblem may occur in that all control information cannot be transmittedthrough the control channel 904. In this case, the basic data channel903 can function as part of the control channel 903. The basic datachannel 903 can also function as a data channel, similar to the otherextended data channels 901, 902, 905, and 906. Services provided throughthe basic data channel 903 may be mandatory services that must beessentially provided by the communication protocol.

As shown in FIG. 11, the CR technique is characterized in that frequencybands used by channels change with time since the CR technique is notlimited to specific frequency bands. In the case of FIG. 11, the datachannels 901, 902, 903, 905, and 906 are used by different componentMACs/PHYs. That is, the first of the specific services is provided by asecond component MAC/PHY (Component 2 MAC/PHY) through the data channels901 and 905. The second service is provided by a third component MAC/PHY(Component 3 MAC/PHY) through the data channel 902. The third service isprovided by a first component MAC/PHY (Component 1 MAC/PHY) through thedata channel 903 and the fourth service is provided by a fourthcomponent MAC/PHY (Component 4 MAC/PHY) through the data channel 906.

As shown, each service may be provided through adjacent frequency bandsor through separate frequency bands depending on the configuration (orsetting) of the platform MAC/PHY. Similarly, a single component MAC/PHYmay communicate through adjacent frequency bands or through separatefrequency bands depending on the configuration of the platform MAC/PHY.

Reference will now be made to a payload management for componentMACs/PHYs.

As described above, if the platform MAC/PHY determines the amount of aspectrum to be used, this data is standardized and broadcast through acontrol channel such as the channel 904 of FIG. 11 to inform allterminals of the determined amount of the spectrum. Through thisbroadcast data, CR terminals receive their desired services from acorresponding base station.

Actually, the CR terminal receives a service through a componentMAC/PHY. That is, component MACs/PHYs of the CR terminal provideinterfaces for services. The component MACs/PHYs are divided into twomodes according to whether or not they have a standalone transmissionsignal protocol (i.e., an RF signal protocol). In the case of the firstmode, a physical transmission signal protocol of the component MAC/PHYcomplies with the protocol of the platform MAC/PHY while an innerpayload structure alone is implemented using the component MAC/PHY. Inthe case of the second mode, a physical transmission signal protocol ofthe component MAC/PHY is defined independently. The first mode is adependent component MAC/PHY definition method and the second mode is anindependent component MAC/PHY definition method.

The following is a description of the dependent component MAC/PHYdefinition method. In this case, since physical signal protocols of thecomponent MACs/PHYs of the terminal are defined according to theprotocol of the platform MAC/PHY, the component MACs/PHYs of theterminal can directly access services without undergoing a process suchas individual physical synchronization or virtual base station scanningaccording to each service. However, it is preferable to define dependentcomponent MACs/PHYs that provide access structures capable of providingdifferent qualities of service (QoS) according to supported traffictypes while providing separate definitions of transmission chains ofup/down links defined according to the service protocol. Thetransmission chain corresponds to the order of packets transferred froman upper layer (for example, a layer provided above the MAC layer) andis valid until it is transmitted as a physical signal. Examples of thetransmission chain include retransmission, scheduling, channel coding,Hybrid ARQ, MIMO, and fragmentation. The QoS of a packet transmittedaccording to the transmission chain is determined according to thetransmission format or structure of the packet. Each QoS can beclassified according to the protocol type. For example, the WLAN doesnot support real time transmission while the IEEE 802.16e supports realtime transmission. Accordingly, it is preferable to provide accessstructures capable of providing different QoS according to the supportedtraffic types.

Reference will now be made to an independent component MAC/PHYdefinition method. In this case, after the platform MAC/PHY determines afrequency band, the fact that a specific service is in use in a specificband is marked in a control channel. For example, notification that aspecific service is provided through the bands 901 to 906 is providedthrough the channel 904 in FIG. 11. A physical transmission signalprotocol for accessing each band to receive a service is defined in eachcomponent MAC/PHY. That is, the independent component MAC/PHY definitionmethod is a method in which the platform MAC/PHY performs an operationfor providing information about each band through a control channel andthe component MACs/PHYs perform the other operations. This method willbe preferred since it can accommodate a variety of current wirelesscommunication devices without change. In this case, the platform MAC/PHYmust provide information regarding a channel which each componentMAC/PHY must access since each component MAC/PHY provides an interfacefor a conventional limited bandwidth (for example, a specific bandwidthused in the conventional CDMA communication protocol). That is, theplatform MAC/PHY needs to define interfaces for the control channel (forexample, the channel 904 of FIG. 11) and a data channel (for example,the channel 903 or a data channel included in the channel 904) that mustbe defined and to instruct a specific component MAC/PHY to be used foran extended band (for example, the channel 901, 902, 905, or 906 of FIG.11).

The platform MAC/PHY concept can be advantageously used forcommunication providers that provide services to regions with differentpopulations. That is, the platform MAC/PHY concept makes it possible notonly to provide the method of providing a service according to theamount of traffic as described above but also to provide a differentservice according to the region where the service is provided. Forexample, it is possible to provide a new service competition mode takinginto consideration that fact that rural and urban areas have differentpopulations of users.

FIG. 12 illustrates frequency bands used in areas with differentpopulations of users.

In FIG. 12, “Provider 1” and “Provider 2” denote dominant providers inthe market. According to the CR technique, different providers maycoexist with bands of providing specific services for CR terminals Inthis case, dominant providers in the market may install CR communicationdevices in all areas with high populations of users and all areas withlow populations of users in order to provide services to all the areas.However, it is difficult for general providers to install CRcommunication devices in all areas with high populations of users andall areas with low populations of users even though they desire toprovide their services to all the areas. In this case, general providersmay install their CR communication devices (for example, CR basestations) only in areas with high user populations while providingservices through CR communication devices of dominant providers in areaswith low user populations. Particularly, different providers may sharethe same bands through the CR technique and each provider may chargefees for their unnecessary bands to other providers after lending theunnecessary bands to them. In another possible method, a specificprovider borrows frequency bands from other providers for further use ofbands capable of providing services.

Those skilled in the art will appreciate that the present invention maybe embodied in other specific ways than those set forth herein withoutdeparting from the spirit and essential characteristics of the presentinvention. The above description is therefore to be construed in allaspects as illustrative and not restrictive. The scope of the inventionshould be determined by reasonable interpretation of the appended claimsand all changes coming within the equivalency range of the invention areintended to be embraced in the scope of the invention.

The present invention can achieve the following advantages. First, thepresent invention allows efficient use of idle spectrums. A specificembodiment of the present invention also allows different providers toshare spectrums allocated to the providers.

An embodiment of the present invention defines a comprehensive MAC/PHYformat for CR terminals. This embodiment can provide a variety ofqualities of service (QoS) since service types usable in CRcommunication devices are implemented in platform MACs/PHYs. Accordingto an embodiment, it is possible to effectively eliminate channelcongestion that users feel for burst traffic, compared to the method ofreducing the QoS provided to the users.

Each of the embodiments of the present invention suggests a standardprotocol form that can evolve on its own. That is, the present inventioncan provide CR terminals with a comprehensive framework for both currentwireless communication technologies and future communicationtechnologies.

What is claimed is:
 1. A method for a terminal to communicate with anetwork using a plurality of frequency band cells, the methodcomprising: acquiring frequency bands information on which of frequencybands measurement can be performed and on which of the frequency bandsmeasurement cannot be performed, wherein the frequency bands informationis acquired from outside of the terminal; performing measurement on thefrequency bands on which measurement can be performed based on thefrequency bands information; acquiring measurement result information onthe plurality of frequency band cells based on the measurement; andcommunicating data with a network on the plurality of frequency bandcells considering the measurement result information.
 2. The method ofclaim 1, wherein the frequency bands information includes a list ofblacklisted cells which are not considered at performing measurement. 3.The method of claim 1, wherein the plurality of frequency band cellsincludes a primary frequency band cell, and wherein the primary bandcell is used for receiving access information about the plurality offrequency band cells.
 4. The method of claim 1, wherein the plurality offrequency band cells includes a frequency band cell including contiguousfrequency bands.
 5. The method of claim 1, wherein the plurality offrequency band cells includes a frequency band cell includingnon-contiguous frequency bands.
 6. A terminal configured to communicatewith a network using a plurality of frequency band cells, the terminalcomprising: a transceiver configured to transmit and receive radiofrequency signals; and a processor connected to the transceiver andconfigured to: acquire frequency bands information on which of frequencybands measurement can be performed and on which of the frequency bandsmeasurement cannot be performed, wherein the frequency bands informationis acquired from outside of the terminal, perform measurement on thefrequency bands on which measurement can be performed based on thefrequency bands information, acquire measurement result information onthe plurality of frequency band cells based on the measurement, andcommunicate data with a network on the plurality of frequency band cellsconsidering the measurement result information.
 7. The terminal of claim6, wherein the frequency bands information includes a list ofblacklisted cells which are not considered at performing measurement. 8.The terminal of claim 6, wherein the plurality of frequency band cellsincludes a primary frequency band cell, and wherein the primary bandcell is used for receiving access information about the plurality offrequency band cells.
 9. The terminal of claim 6, wherein the pluralityof frequency band cells includes a frequency band cell includingcontiguous frequency bands.
 10. The terminal of claim 6, wherein theplurality of frequency band cells includes a frequency band cellincluding non-contiguous frequency bands.